package com.italicatab;


import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.widget.ImageView;

import java.io.*;
import java.net.URL;
import java.util.HashMap;
import java.util.Stack;


public class clsLazyLoad {

    private Context CONTEXT;
    private Activity ACTIVITY;
    // the simplest in-memory cache implementation. This should be replaced with
    // something like SoftReference or BitmapOptions.inPurgeable(since 1.6)
    private HashMap<String, Bitmap> cache = new HashMap<String, Bitmap>();

    private File cacheDir;
    private Boolean COMPRESS_WHILE_READING_FROM_DISK = false;

    public clsLazyLoad(Context context, Boolean compressWhileReadingFromDisk) {
        CONTEXT = context;
        COMPRESS_WHILE_READING_FROM_DISK = compressWhileReadingFromDisk;
        // Make the background thread low priority. This way it will not affect
        // the UI performance
        photoLoaderThread.setPriority(Thread.NORM_PRIORITY - 1);

        // Find the dir to save cached images
        if (android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED))
            cacheDir = new File(android.os.Environment.getExternalStorageDirectory(), "Italica");
        else
            cacheDir = context.getCacheDir();
        if (!cacheDir.exists())
            cacheDir.mkdirs();
    }

    // Temp image until actual one loads
    final int stub_id = R.drawable.sample_image;

    public void DisplayImage(String url, Activity activity, ImageView imageView) {
        ACTIVITY = activity;
        if (cache.containsKey(url))
            imageView.setImageBitmap(cache.get(url));
        else {
            queuePhoto(url, activity, imageView);
            imageView.setImageResource(stub_id);
        }
    }

    private void queuePhoto(String url, Activity activity, ImageView imageView) {
        // This ImageView may be used for other images before. So there may be
        // some old tasks in the queue. We need to discard them.
        photosQueue.Clean(imageView);
        PhotoToLoad p = new PhotoToLoad(url, imageView);
        synchronized (photosQueue.photosToLoad) {
            photosQueue.photosToLoad.push(p);
            photosQueue.photosToLoad.notifyAll();
        }

        // start thread if it's not started yet
        if (photoLoaderThread.getState() == Thread.State.NEW)
            photoLoaderThread.start();
    }

    private Bitmap getBitmap(String url) {
        // I identify images by hashcode. Not a perfect solution, good for the
        // demo.
        String filename = String.valueOf(url.hashCode());
        File f = new File(cacheDir, filename);

        // from SD cache
        Bitmap b = decodeFile(f);
        if (b != null)
            return b;

        // from web
        try {
            Bitmap bitmap = null;
            InputStream is = new URL(url).openStream();
            OutputStream os = new FileOutputStream(f);
            utils.CopyStream(is, os);
            os.close();
            bitmap = decodeFile(f);
            return bitmap;
        } catch (Exception ex) {
            ex.printStackTrace();
            return null;
        }
    }

    // decodes image and scales it to reduce memory consumption
    private Bitmap decodeFile(File f) {
        if (COMPRESS_WHILE_READING_FROM_DISK == true) {
            try {
                // decode image size
                BitmapFactory.Options o = new BitmapFactory.Options();
                o.inJustDecodeBounds = true;
                BitmapFactory.decodeStream(new FileInputStream(f), null, o);

                // Find the correct scale value. It should be the power of 2.
                final int REQUIRED_SIZE = 70;
                int width_tmp = o.outWidth, height_tmp = o.outHeight;
                int scale = 1;
                while (true) {
                    if (width_tmp / 2 < REQUIRED_SIZE
                            || height_tmp / 2 < REQUIRED_SIZE)
                        break;
                    width_tmp /= 2;
                    height_tmp /= 2;
                    scale++;
                }

                // decode with inSampleSize
                BitmapFactory.Options o2 = new BitmapFactory.Options();
                o2.inSampleSize = scale;
                return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
            } catch (FileNotFoundException e) {
            }

            return null;
        } else {
            Bitmap _bitmap = BitmapFactory.decodeFile(f.getAbsolutePath());
            return _bitmap;
        }
    }

    // Task for the queue
    private class PhotoToLoad {

        public String url;
        public ImageView imageView;

        public PhotoToLoad(String u, ImageView i) {
            url = u;
            imageView = i;
        }
    }


    PhotosQueue photosQueue = new PhotosQueue();

    public void stopThread() {
        photoLoaderThread.interrupt();
    }

    // stores list of photos to download
    class PhotosQueue {

        private Stack<PhotoToLoad> photosToLoad = new Stack<PhotoToLoad>();

        // removes all instances of this ImageView
        public void Clean(ImageView image) {
            for (int j = 0; j < photosToLoad.size(); ) {
                if (photosToLoad.get(j).imageView == image)
                    photosToLoad.remove(j);
                else
                    ++j;
            }
        }
    }


    class PhotosLoader extends Thread {

        public void run() {
            try {
                while (true) {
                    // thread waits until there are any images to load in the
                    // queue
                    if (photosQueue.photosToLoad.size() == 0)
                        synchronized (photosQueue.photosToLoad) {
                            photosQueue.photosToLoad.wait();
                        }
                    if (photosQueue.photosToLoad.size() != 0) {
                        PhotoToLoad photoToLoad;
                        synchronized (photosQueue.photosToLoad) {
                            photoToLoad = photosQueue.photosToLoad.pop();
                        }
                        Bitmap bmp = getBitmap(photoToLoad.url);
                        cache.put(photoToLoad.url, bmp);
                        if (((String) photoToLoad.imageView.getTag()).equals(photoToLoad.url)) {
                            BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad.imageView);
                            //Activity a = (Activity) photoToLoad.imageView.getContext();
                            //a.runOnUiThread(bd);
                            ACTIVITY.runOnUiThread(bd);
                        }
                    }
                    if (Thread.interrupted())
                        break;
                }
            } catch (InterruptedException e) {
                // allow thread to exit
            }
        }
    }


    PhotosLoader photoLoaderThread = new PhotosLoader();


    // Used to display bitmap in the UI thread
    class BitmapDisplayer implements Runnable {

        Bitmap bitmap;
        ImageView imageView;

        public BitmapDisplayer(Bitmap b, ImageView i) {
            bitmap = b;
            imageView = i;
        }

        public void run() {
            if (bitmap != null)
                imageView.setImageBitmap(bitmap);
            else
                imageView.setImageResource(stub_id);
        }
    }

    public void clearCache() {
        // clear memory cache
        cache.clear();

        // clear SD cache
        File[] files = cacheDir.listFiles();
        for (File f : files)
            f.delete();
    }
}


class utils {

    public static void CopyStream(InputStream is, OutputStream os) {
        final int buffer_size = 1024;
        try {
            byte[] bytes = new byte[buffer_size];
            for (; ; ) {
                int count = is.read(bytes, 0, buffer_size);
                if (count == -1)
                    break;
                os.write(bytes, 0, count);
            }
        } catch (Exception ex) {
        }
    }
}